JP2649681B2 - Anti-skid device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an anti-skid device for operating a braking device of an automobile efficiently without a loss due to slip, and in particular, to a program for a defect of a wheel speed sensor of a non-driving wheel. The present invention relates to an anti-skid device that can be detected in a targeted manner.

[Conventional technology and its problems]

Conventionally, in this type of anti-skid device, when it is detected that a tendency to lock the wheels has occurred, a brake force release command is issued, and in response to the command, the solenoid of the pressure control valve of the wheel cylinder is operated. Opening and closing the pressure control valve, causing the hydraulic circuit to perform the pressure reducing operation, and conversely, the lock is restored, a braking command is issued, and similarly, the solenoid is driven to open and close the pressure control valve, and the hydraulic pressure is controlled. A pressurizing operation is performed so that the circuit communicates with the hydraulic pressure source.

However, in order to detect such a tendency to lock the wheels or a tendency to recover the locks, generally, a method is employed in which it is determined whether the slip speed (= estimated vehicle speed-wheel speed) exceeds a certain threshold value. .

The estimated vehicle speed is calculated using the high-speed side or the average value of the non-drive wheels, such as the rear wheels in the case of a front wheel drive vehicle and the front wheels in the case of a rear wheel drive vehicle.

Therefore, when the wheel speed sensors of all the non-driving wheels are abnormal, the anti-skid control device, for example, even if the actual car is running, the car stops because there is no sensor output from the non-driving wheels. There is a problem that it is considered that there is a mistake, and controls are performed with wrong judgment.

An object of the present invention is to solve the above-described problem by judging a numerical value output from a speed sensor of a non-driven wheel programmatically.

[Means for solving the problem]

In order to solve the above-mentioned problem, in the present invention, in a state where the wheel speed from the drive wheel speed sensor continuously reaches the predetermined speed, the predetermined speed is obtained from all the non-drive wheel sensors. If time is not detected, a means for outputting a sensor abnormality signal of the non-driving wheel is provided.

[Action]

In a state where the driving wheels continuously reach a predetermined speed, that is, in a state where it is considered that the vehicle is traveling stably, the wheel speeds from all the non-driving wheel sensors are determined by comparing them with a predetermined reference value,
If the abnormality is prolonged by waiting for a certain time to elapse, it is detected that some abnormality has occurred in the wheel speed sensor, its circuit, and the like.

〔Example〕

FIG. 1 is a schematic electrical diagram of an anti-skid device. As shown, the signals of the wheel speed sensors S ₁ to S ₄ is inputted to an electronic control unit (hereinafter referred to as ECU), various calculations, after the determination, the pressure control valve of the wheel cylinder for actuating the wheel brakes ( Solenoids SOL _{1 to} SOL _{6 (} not shown)
And opens and closes a relay ML of a motor M that drives a pump P of a hydraulic unit (not shown) to increase and maintain the hydraulic pressure with respect to the wheel cylinder of each wheel brake.
Reduce pressure. Here, the six Sorunoido SOL ₁ ~SOL ₆ is shown, three channels, that is, the left and right wheels and the rear wheels of the front wheels, indicating that the control of the hydraulic pressure is performed.

Further, when the above-mentioned ECU internal monitoring circuit detects an abnormality, warning lamp W ₁ is turned to open the fail-safe relay FL, releases the control of the anti-skid device,
Normal brake operation can be performed.

In the drawing, + B indicates that the power supply is connected,
₁ indicates that it is connected to a power supply via an ignition switch.

FIG. 2 schematically shows the functions of the ECU. Wheel speed sensor S
Since the output signal of ₁ to S ₄ is an AC voltage signal, which is converted into a pulse by the interface circuit, in the pulse processing circuit, a pulse count and calculation are performed, and the numerical CPU program operation, analysis, Then, based on the result, a command is issued to the solenoid drive circuit and the motor relay drive circuit, and the solenoids SOL _{1 to} SO
L ₆ and driving the motor relay ML.

Also, denotes a CPU, to determine the speed of the non-driven wheels, the program has been built to light the warning lamp W ₁ by the result.

More specifically, as shown in FIG. 3, deceleration and estimated vehicle speed are calculated from the wheel speeds supplied by the wheel speed detecting means including the wheel speed sensor, the interface circuit, and the pulse processing circuit. The lock state detecting means detects that the locking tendency of the wheel has occurred by comparing with a reference value such as that the vehicle speed becomes equal to or less than a predetermined value or the slip speed (difference between the estimated vehicle body speed and the wheel speed) becomes equal to or more than a predetermined value. Issue a pressure reduction command for the drive circuit. Therefore, the solenoid drive circuit excites the solenoid SOL ₁ and
When SOL _{2 is} also excited, both the pressure control valves 1 and 2 move to the right to cut off the hydraulic circuit of the wheel cylinder 4 from the master cylinder 3 and to connect the circuit between the wheel cylinder 4 and the reservoir 5, The brake fluid pressure drops.

When the wheel speed starts to recover and the deceleration or slip speed exceeds a certain reference value, it is determined that the risk of locking has been avoided, and the lock state detecting means issues a pressurizing command to the solenoid drive circuit. . Therefore, when the solenoid drive circuit demagnetizes the solenoids SOL ₁ and SOL ₂ and returns the pressure control valves 1 and 2 to the state shown in FIG. 3, the hydraulic pressure source and the hydraulic circuit of the wheel cylinder 4 communicate, and the brake Pressure rises.

In some cases, while the pressure-reducing command is issued, the pressure-reducing command is issued by interrupting this command. In this case, the solenoid SOL ₁ may be excited and the solenoid SOL ₂ may be demagnetized. For this reason, the pressure control valve 1 moves to the right in the figure to cut off the hydraulic circuit, but since the pressure control valve 2 is at the position shown in the figure, the hydraulic pressure is confined in the wheel cylinder 4 and the brake is released. The pressure is kept constant.

Such an operation is performed for each of the three channels of the left and right front wheels and the rear wheels as described above. However, it is not limited to this. All four wheels, that is, four channels may be used.

The calculation and lock state detecting means is connected to means for detecting and determining whether the speeds of all the non-driven wheels have been within a certain range for a predetermined time.

FIG. 4 shows a processing flow of such detection and determination means and anti-skid control.

Now, the wheel speed sensor of the drive wheel the S ₁ and S _2, S ₃ and S ₄
Is a wheel speed sensor for the non-driven wheels.

First, performs initial setting in the initial step 1, the counter is cleared, and stores the previous wheel speed wheel speed V _W to temporary sensor S ₁ and S ₂ of the current (present), in Step 2, the previous drive rate from sensor S ₁ or S ₂ of wheels see if certain level. If it is not more than a certain value, step 3 is entered. Step 3 corresponds to the anti-skid control, that is, the calculation and lock state detecting means.

Subsequent to step 3, in step 4, sensors S ₁ and S ₂
Store the current wheel speed V _W from the previous wheel speed,
Return to step 2.

If the condition of YES is satisfied in step 2, step 5
In, this time of the wheel speed V _W of the sensor S _1, S ₂ is looking at whether certain level or more. The reference value for the determination at this time is the same as in step 2, and is set to a relatively low level, for example, 20 km / hour.

The above steps 2, 4 and 5, the sensor of the driving wheel S ₁ or
It is for continuing the wheel speed detected from S ₂ to determine if it has reached the certain level.

In step 6, the current wheel speed V _W of the non-driven wheel sensor S ₃ and S ₄ to determine if within a certain range. The value of the predetermined range, for example, may be a current wheel speed ± 10% of the sensor S ₁ and S _2.

If the condition of NO is satisfied in step 6, 1 is added to the counter (step 7). Then, in step 8, the counter is compared with the reference value k. This counter indicates the accumulated time (contents of the counter × 8 ms) in which it is considered that an abnormality occurs in the speed detection of the sensors S ₃ and S ₄ if the anti-skid control is performed in a cycle of 8 msec. .

In step 8, if YES condition is satisfied, the sensor S _3, S ₄ and outputs an error signal, (step 9), for example, or to light the lamp W _1, by operating the fail saver furyl over FL, The anti-skid control device may be disabled. In any case, the subsequent processing of this output signal is optional. If the condition of NO is satisfied in step 8, it is determined that the sensors S ₃ and S ₄ and their circuits are normal, and the process returns to step 3.

〔effect〕

According to the present invention, as described above, when the driving wheels are considered to be in a stable traveling state, if the predetermined speed is not detected for a predetermined time from the speed sensors of all the non-driving wheels, Since the signal is issued, the abnormality of the speed detecting means of the non-driving wheel can be surely known.

[Brief description of the drawings]

FIG. 1 is an electrical system diagram of the anti-skid device, FIG. 2 is a block diagram schematically showing the electronic control device of the above, FIG. 3 is a diagram showing the relationship between the electronic control device and the hydraulic circuit, and FIG. Third
It is a flowchart which shows the logic of the wheel speed detection determination means of the non-drive wheel of the figure. S _{1 to} S ₆ …… wheel speed sensor, SOL _{1 to} SOL ₂ …… solenoid,
M: Motor, P: Pump, ML: Motor relay, FL
… Fail safe relay, W ₁ …… Warning lamp.

Claims (1)

(57) [Claims] An operation is performed based on a wheel speed signal from a wheel speed detecting means including a wheel speed sensor to detect that a wheel is in a lock tendency or a recovery tendency from a lock,
An anti-compression and lock state detecting means for outputting brake pressure decreasing, holding and pressurizing signals, respectively, and a solenoid driving means for driving a solenoid of a pressure control valve of a hydraulic circuit in accordance with an output signal of the detecting means. In the skid device, if a predetermined speed is not detected from all the non-driving wheels for a predetermined time in a state where the driving wheel speed from the wheel speed detecting means continuously reaches a predetermined speed, a sensor abnormality of the non-driving wheel is detected. An anti-skid device comprising means for outputting a signal.